US President Donald Trump says he has signed a new executive order to keep open the notorious Guantánamo Bay prison in Cuba.

"I just signed, prior to walking in, an order directing (Defense) Secretary (Jim) Mattis ... to re-examine our military detention policy and to keep open the detention facilities in Guantánamo Bay," Trump said in his State of the Union speech on Tuesday night, presstv.com reported.

Trump said that new prisoners, including members of terrorist groups like Daesh, will also be sent to the military facility.

"I am asking Congress to ensure that in the fight against ISIS and al Qaeda we continue to have all necessary power to detain terrorists wherever we chase them down, wherever we find them. And In many cases for them it will now be Guantánamo bay."

"The United States may transport additional detainees to US Naval Station Guantanamo Bay when lawful and necessary to protect the nation," the order said.

The order described the detention operations at the prison "legal, safe, humane, and conducted consistent with United States and international law."

Trump’s decision reversed the unsuccessful attempt by his predecessor to shutter the controversial camp, which currently holds 41 inmates, down from 800 after its 2002 opening in the aftermath of the 9/11 attacks.

Barack Obama had pledged during his 2008 presidential campaign to close the military prison, but failed to fulfill his promise in the face of stiff opposition from the Congress.

In a speech in December 2016, he expressed disappointment over failure to close the prison during his term in office, saying it was a disgrace and a waste of money.

"We are wasting hundreds of millions of dollars to keep fewer than 60 people in a detention facility in Cuba,” the former president said during his last security speech in the US state of Florida. “That’s not strength … And I will continue to do all that I can to remove this blot on our national honor."

A Senate report in December 2014 revealed that the CIA had used a wide array of sexual abuse and other forms of torture as part of its interrogation methods against the prisoners at Guantanamo.